Displaying book titles

[jhaag4]

So I have a form with a menu bar and a listbox. On the menu bar is the Display option with 3 choices; all, fiction, or nonfiction. The textfile has book titles, author, category (fic"F" or nonfic"N"), stock, price, in that order. When the user clicks on "Display" "all", I want all the titles to display in the listbox. If they click on "Nonfic", just the nonfic titles, and same with "fiction". This is my code so far:

Private Sub menuDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles menuDisplay.Click

Dim books() As String = IO.File.ReadAllLines("Books.txt")
Dim data() As String
Dim allBooksTitle, allNonFicTitle, allFicTitle As String

For i As Integer = 0 To books.Count - 1
data = books(i).Split(","c)
allBooksTitle = data(2)
If data(2).Trim = "N" Then
allNonFicTitle = data(0)
ElseIf data(2).Trim = "F" Then
allFicTitle = data(0)
End If
Next

' show result
If menuDisplayAll.Checked Then
menuDisplayFic.Checked = False
menuDisplayNonFic.Checked = False
lstBox.Items.Clear()
lstBox.Items.Add(allBooksTitle)
ElseIf menuDisplayFic.Checked Then
menuDisplayNonFic.Checked = False
menuDisplayAll.Checked = False
lstBox.Items.Clear()
lstBox.Items.Add(allFicTitle)
ElseIf menuDisplayNonFic.Checked Then
menuDisplayFic.Checked = False
menuDisplayAll.Checked = False
lstBox.Items.Clear()
lstBox.Items.Add(allNonFicTitle)
End If
End Sub

Yet, Every time I debug it, to actually get the titles to show up in the listbox after i check one option, I have to click the values button again. Also, it only shows one book title or both the nonfiction and the fiction, and then for all book it only shows "N". I don't know what I am doing wrong. Any help would be appreciated!

[kareninstructor]

Here is a conceptual example of working with your data (my source I am sure is slightly different than yours yet you can adapt). No UI controls are used, should be easy for you to work out.

Dim dt As New DataTable

dt.Columns.Add(New DataColumn With {.ColumnName = "Title", .DataType = GetType(String)})
dt.Columns.Add(New DataColumn With {.ColumnName = "Author", .DataType = GetType(String)})
dt.Columns.Add(New DataColumn With {.ColumnName = "Category", .DataType = GetType(String)})
dt.Columns.Add(New DataColumn With {.ColumnName = "Stock", .DataType = GetType(Int32)})
dt.Columns.Add(New DataColumn With {.ColumnName = "Price", .DataType = GetType(Decimal)})

Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser("Books.txt")
    MyReader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
    MyReader.Delimiters = New String() {","}
    Dim Row As String()
    While Not MyReader.EndOfData
        Try
            Row = MyReader.ReadFields()
            dt.Rows.Add(New Object() _
                {
                    Row(0),
                    Row(1),
                    IIf(Row(2) = "F", "Fiction", "Non-Fiction").ToString,
                    CInt(Row(3)),
                    CDec(Row(4))
                }
            )
        Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
            Console.WriteLine(ex.Message)
        End Try
    End While
End Using


Dim dvFiction As DataView = dt.DefaultView
dvFiction.RowFilter = "Category = 'Fiction'"
For Each row As DataRowView In dvFiction
    Console.WriteLine(String.Join(",", row.Row.ItemArray))
Next
Console.WriteLine()
Dim dvNonFiction As DataView = dt.DefaultView
dvFiction.RowFilter = "Category = 'Non-Fiction'"
For Each row As DataRowView In dvNonFiction
    Console.WriteLine(String.Join(",", row.Row.ItemArray))
Next

File Books.txt

Title1,Bob Smith,F,10,12.99
Title2,Jane Anderson,N,2,3.99
Title3,Serge Abiteboul,F,5,10.78
Title4,Dan Suciu,N,3,23.87

Results

Title1,Bob Smith,Fiction,10,12.99
Title3,Serge Abiteboul,Fiction,5,10.78

Title2,Jane Anderson,Non-Fiction,2,3.99
Title4,Dan Suciu,Non-Fiction,3,23.87